They may possess root-like, leaf-like or stem-like structures. They lack true roots, stem or leaves. Such a classification for flowering plants was given by George Bentham and Joseph Dalton Hooker. Chlorella and Spirullina are unicellular algae, rich in proteins and are used as food supplements even by space travellers. Pteridophytes are used for medicinal purposes and as soil-binders. In some cases sporophylls may form distinct compact structures called strobili or cones Selaginella, Equisetum. Within the ovule is the female gametophyte or embryo sac which contains the egg cell.
Being photosynthetic they increase the level of dissolved oxygen in their immediate environment. Following fertilisation the zygote also divides by mitosis to produce a diploid sporophytic plant body. Storage of food: Underground stems are modified for storage of food. These in turn, divide by mitosis to form a haploid plant body once again. The sex organs in bryophytes are multicellular. The female sex organ called archegonium is flask-shaped and produces a single egg. Special focus is on the endocrine system of humans, the hormones secreted by them, the functions of said hormones and the disorders caused by excess or deficit of the same.
The two follows each other. This chapter concludes Unit 5, Human Physiology. Algae usually reproduce vegetatively by fragmentation, asexually by formation of different types of spores and sexually by formation of gametes which may show isogamy, anisogamy or oogamy. Bryophytes and pteridophytes, interestingly, exhibit an intermediate condition Haplo-diplontic ; both phases are multicellular and often free-living. Since fertilisation takes place twice, it is called double fertilisation. They also get to learn the mechanims of seeing and hearing with the help of clear diagrams.
They come to know of cyclic and non-cyclic photo-phosphorylation. It covers important questions with comprehensive answers. Class 11 Biology Chapter 2 Biological Classification This chapter further leads the student into the world of biologic classification. Now, this might take some time to develop and get good at, but the reward is worth it. This chapter concludes Unit 3, Cell: Structure and functions. Question 8: Explain briefly the following terms with suitable examples:- i protonema ii antheridium iii archegonium iv diplontic v sporophyll vi isogamy Question 9: Differentiate between the following:- i red algae and brown algae ii liverworts and moss iii homosporous and heterosporous pteridophyte iv syngamy and triple fusion Question 10: How would you distinguish monocots from dicots? Leaves may be simple or compound. In conifers, the needle-like leaves reduce the surface area.
After fertilisation, the zygote develops into a sporophyte, consisting of a foot, seta and capsule. These organs possess well-differentiated vascular tissues. Biology is a subject that tells us all about the natural world. The two kinds of spores are produced within sporangia that are borne on sporophylls which are arranged spirally along an axis to form lax or compact strobili or cones. The thallus is dorsiventral and closely appressed to the substrate. Plant cell wall consists of cellulose, hemicellulose, pectins and proteins.
Green algae usually have a rigid cell wall made of an inner layer of cellulose and an outer layer of pectose. Pollen grain, after dispersal from the anthers, are carried by wind or various other agencies to the stigma of a pistil. Class 11 Biology ncert Solutions in pdf for free Download are given in this website. They learn about the deficiency symptoms indicating the lack of said minerals too, for a holistic view on the topic. Zygotes do not undergo reduction division immediately. In this chapter, they are introduced to the mechanism in such a beautiful way as to make them fall in love with the subject.
Also, the artificial systems gave equal weightage to vegetative and sexual characteristics; this is not acceptable since we know that often the vegetative characters are more easily affected by environment. This stage bears the sex organs. They range from simple branched, filamentous forms Ectocarpus to profusely branched forms as represented by kelps, which may reach a height of 100 metres. The pollen grain is released from the microsporangium. No live animals or specimen should be displayed. Spores produced within the capsule germinate to form free-living gametophytes. One of the gymnosperms, the giant redwood tree Sequoia is one of the tallest tree species.
The revision notes covers all important formulas and concepts given in the chapter. The antherozoids are released into water where they come in contact with archegonium. Such reproduction is called isogamous. The chapter also includes the various food components essential in our daily diet, and expounds on the problems caused by the deficiency of them. The angiosperms are an exceptionally large group of plants occurring in wide range of habitats. The sporophytes bear sporangia that are subtended by leaf-like appendages called sporophylls. Mosses along with lichens are the first organisms to colonise rocks and hence, are of great ecological importance.
Plant tissue can be broadly categorised into meristematic and permanent. The pteridophytes are further classified into four classes: Psilopsida Psilotum ; Lycopsida Selaginella, Lycopodium , Sphenopsida Equisetum and Pteropsida Dryopteris, Pteris, Adiantum. Some algae may store food in the form of oil droplets. Number and codes are assigned to all the characters and the data are then processed. Drawing Diagrams are the prominent part of. Question 4: Mention the ploidy of the following: protonemal cell of a moss; primary endosperm nucleus in dicot, leaf cell of a moss; prothallus cell of a fern; gemma cell in Marchantia; meristem cell of monocot, ovum of a liverwort, and zygote of a fern. Species of Sphagnum, a moss, provide peat that have long been used as fuel, and because of their capacity to hold water as packing material for trans-shipment of living material.
These solutions explain all the important concepts like Biological Classification, the various kingdoms, Morphology, Structural Organisation, Biomolecules, Cell Division, transport in Plants, Nutrition, Photosynthesis, and more. Furthermore, all solutions are presented in an easy-to-understand format. Alternation of generation Different plant groups complete their life cycles in different patterns. These branches are called stolons. Exchange of gases like Oxygen and Carbondioxide and their transport is discussed in detail. On the other extreme, is the type wherein the diploid sporophyte is the dominant, photosynthetic, independent phase of the plant.